Items used during spell casting are only there to help the caster focus their energy. Having a focal point helps to center your magic on specific things and can create more vivid visualization but it isn't neccessary. The only things that are neccessary for spell casting are a clear mind and strong will.

The Magick that requires no tools and is done in your head is called "Intristic Magick".
Not all spells can be done intristically, but most sympathetic spells can.
However, if you do decide to do a spell or working in your head without any tools, it's best to use the same saftey precautions as you would in any physical magickal working. (I.e. Casting a circle, extinguishing candles that are a hazard, etc)

Items help the spell but it comes down to your energy and focus, so you could cast a spell by focusing energy and visualizing. Example being the 'evil eye' where someone would glare at you sending a curse in your direction.

My brother an I were taught with no tools at all and we manage just fine. Most tools are just symbols anyway which not have meaning if you choose a path that used them. I'm not denying that they have some practical purposes as well however they are not essential as long as you have energy will and intent you should be okay. However if you decide you want to become Wiccan or choose a path laden with paraphernalia you will probably run into some issues.